Process for the manufacture of diolefins from alcohols and aldehydes



Patented Sept. 29, 1942 PROCESS FOR THE MANUFACTURE OF DI- OLEFINS FROMALCOHOLS AND ALDE- HYDES Alessandro Maximoil and Oberto Oanonioi, Milan,Italy; vestedintheAlienPropcrty Custodian No Drawing. ApplicationJanuary 26, 1940, Serial No. 815,880. In Italy February 15, 1939 8Claims. (Cl. 260-681) The object of the present invention is themanufacture of dioleflns by reaction of an alcohol upon an aldehyde athigh temperature in the presence of sulphates or of basic sulphates ofaluminium.

While it was known since 1915 (Ostromissienski Journal Russ. Phys. Chem.Soc. 47, 1472, 1509) that diolefins may be obtained by reacting alcoholsupon aldehydes in the presence of aluminium oxide, it was not knownheretofore that the aluminium sulphates are suitable for the manufactureof dioleiins. The aluminium sulphates may be used directly or they maybe deposited upon in active supports e. g. made of pumice stone,kieselguhr etc. In the latter case the manufacture of the catalyst iscarried out by dissolving or suspending in water the aluminium sulphate,then soaking the support with the solution and thereafter drying theproduct obtained. The aluminium sulphates used for the process inquestion do not require special methods for their manufacture and theusual salts of the commerce may also be used; the basic sulphates may bemanufactured more cheaply by adding aluminium hydrate to a solution ofaluminium sulphate or by adding to a solution of sodium aluminate thenecessary quantity of aluminium sulphate or vice versa.

The alcohol and the aldehyde to be reacted together may be used both inthe ratio of equimolecular weight or different from the equimolecularweight; they may be diluted with substances inert in respect of thereaction e. g.'water or benzol. The reaction may be carried out both atatmospheric pressure or at a lower pressure. The temperature of reactionmay range from 280 to 450 C.

The following examples are given by way of illustration:

Example I.Up'on a catalyst obtained from an aluminium salt of thecomposition heated at 320+360 C. are conveyed the vapours of a liquidhaving the following composition:

The gases issuing from the apparatus of reaction are cooled andpurifled;among them 1.3 butadiene is present in the proportion of +24% by weight.From the condensed vapour ethyl alcohol and acetaldehyde are recovered.In this ,way, by taking into account the alcohol and the acetic aldehydewhich may be recovered, the yield in ethyl alcohol and acetaldehydeconsumed reaches the 33%.

Example IL-A salt of aluminium basic suiphate is obtained by reacting asolution of aluminium sulphate together with a solution of sodiumaluminate. The resulting product is used for the manufacture ofdioleflns, e. g. the piperylene, by reacting upon it, heated at 340-38oc, a mixing consisting of parts of isopropyl alcohol and 40 parts ofacetic aldehyde.

Example HIP-Granules of pumice-stone are soaked with a saturatedsolution of aluminium sulphate; thereafter they are thoroughly dried andare used as catalysts for the manufacture of butadiene from a mixingconsisting of:

The above examples are only by way of iliustration of the invention andare not. limitativ thereof.

Aluminium sulphate manufactured in a manner different from those abovedisclosed may be used. Also other alcohols and other aldehydes may beused for the manufacture of other dioleflns. The reaction may be carriedout at temperature higher or lower than those mentioned in the examples.

What we claim is:

1. A method for manufacturing dioleiin hydrocarbons comprising passingthe vapors of a mixture of a monohydroxy alcohol and aldehydes over acatalyst selected from the group consisting of aluminum sulphates andbasic aluminum sulphates at a temperature of 280-450 C., and separatingthe diolefln hydrocarbons formed from the reaction mixture.

2. A method for manufacturing diolefln hydrocarbons comprising-passingthe vapors of a mixture of a monohydroxy alcohol and aldehydes over acatalyst selected from the group consisting of aluminum sulphates andbasic aluminum sulphates at a temperature of 280-450 C. at atmosphericpressure, and separating the diolefln hydrocarbons formed from thereaction mixture.

over a catalyst selected from the group consisting of aluminum sulphatesand basic aluminum 5. A method of manufacturing 1,3 butadiene comprisingpassin the vapors of a mixture of ethyl alcohol and acetic aldehyde overa catalyst selected from the group consisting of aluminum sulphates andbasic aluminum sulphates at a temperature between 280-450 C.

6. A method of manufacturing piperylene comprising passing the vapors ofa mixture of isopropyl alcohol and acetic aldehyde over basic aluminumsulphates at a temperature of 280- 450 C.

ALESSANDRO MAXIMOFF. OBERTO CANONICI.

